The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jan. 28, 1997
Filed:
Apr. 06, 1995
Jing M Lee, Stafford, TX (US);
Other;
Abstract
A urea production process combining lower pressure urea concentration and carbamate recovery steps into a single non-vacuum operation. Following high pressure stripping wherein a bulk of unreacted carbamate is recovered from the reaction effluent, remaining carbamate is stripped by heated air at atmospheric pressure wherein urea is concurrently concentrated without the use of vacuum evaporators. Weak carbamate solution subsequently formed is stripped of water (and residual urea is hydrolyzed) using air and steam at a medium pressure single tower hydrolyzer/stripper to obtain a concentrated carbamate stream suitable for recycle to the reactor. The process employs heat integration for enhanced energy efficiency and produces a good quality aqueous condensate suitable for direct use as boiler feed water. Thus the aqueous condensate produced requires no additional cooling and ammonia treatment. The process employs simplified and reduced process unit operation to eliminate equipment for cost reduction.